1. Field of the Invention
This invention relates to a data processing apparatus, a data processing method, a data recording medium on which data processing program that is readable by a computer are recorded, and a recording medium, and more particularly to a data processing apparatus, a data processing method, a data recording medium on which data processing program that is readable by a computer are recorded, and a recording medium for preventing illegal distribution of data that are recorded on the recording medium that is installed in the data processing apparatus.
2. Description of the Related Art
In recent years, navigation equipment for automobiles has become widely used as a kind of data processing apparatus that uses a recording medium from which data can be read, and currently in a typical navigation apparatus, the use of an optical disk as the recording medium has become common.
In this case, it has been normal to use a read only optical disk as the optical disk used in the conventional navigation apparatus from which it was only possible to read the data that are recorded on the disk, however, in recent years as navigation equipment has become more functionable, it is desirable that it be possible for the user to write desired data on the optical disk.
Also, in the case of a conventional optical disk, a certain amount of time was required from the time that the detection pickup was moved to a position on the optical where the desired data are recorded, until detection began, so due to the need for quick data acquisition during high-speed movement, there arose a demand for a recording medium that was capable of detecting the desired data more quickly.
Therefore, recently there has been a lot of research into the possibility of using a hard disk, having a large storage capacity and to which data can be written and from which data can be searched at high speed, as the recording medium in a navigation apparatus.
However, currently hard disks are widely used for personal computers, so it is possible to use a personal computer to easily copy the contents of a hard disk, on which special data for a navigation apparatus have been recorded, to another hard disk, and as a result, there is a problem in that it is relatively easy to illegally distribute the hard disk, on which the contents have been copied, for use as the recording medium in another navigation apparatus.